HAWAII ISLAND

The island of Hawaii is the largest (10,438 km2) in the State, measuring 150 by 122 km at its extreme dimension. It is the youngest geologically, having emerged from the ocean between late Pleistocene and Recent time. It was formed as result of five volcanoes three of which were currently or recently active. The peaks of these volcanoes range in altitude from a few hundred feet to 4,206 m, resulting in about 80 % of the island being over 305 m in elevation.

On Hawaii island, 123 perennial streams were reported by Timbol and Maciolek (1978). Fifty-seven percent were continuous and 3 % altered (4 streams). Three of the altered streams were interrupted. Wailoa River, Puna District, is the largest stream based on length and watershed area while Lamimaumau Stream, north of Kamuela, is the smallest.

A total of 4 km of modified channel was reported on the 4 altered streams. Modified sections averaged 7 % (range 0.6 - 12 %) of their combined channel length. The estimated percentage of the 4 km total by channel modification type was:

Lined channel - 44 %

Cleared and/or realigned - 31 %

Revetment - 23 %

Elevated culvert - 2 %

Water is diverted from 60 % of Hawaii island streams and 79 % have road crossings. Only 11 % of the Big Island's streams were reported as physically pristine by Timbol and Maciolek (1978).